The present invention relates to network management and, more specifically, to management for software-defined networks.
Software-defined networks separate the data plane (which performs packet forwarding) and control plane (which decides where to forward packets) in network devices, such as switches or routers (we refer to them simply as switches), by moving the control plane to a logically centralized machine, called the controller. The controller issues commands to the switches (e.g., add, delete, modify forwarding table entries, read state) using a set of APIs; the most popular such communication protocol between the network control and data planes is OpenFlow. OpenFlow enables fine-grained control over the network but is low-level and not suited for applications that have high-level requirements from the network. For example, a distributed application has end-to-end constraints about paths between its endpoints and does not want to (nor knows how to) concern itself about the low-level characteristics that the path needs to satisfy to meet the constraints (e.g., pass through a list of switches, etc.). Thus, there is a disconnect between how the applications want and know to interact with the network (simple interface, similar to the socket interface) and the OpenFlow protocol used to perform the interaction (complex, low-level).
Previous work builds a higher-level programming language on top of OpenFlow (e.g., Frenetic, NetCore) to express packet-forwarding policies. These efforts aim to optimize the OpenFlow forwarding rule generation and to synchronize rules from different applications. However, they are targeted to network operators and do not alleviate the complexity involved in interacting with the network.
We develop a network manager for networks (e.g. OpenFlow networks), called FlowSense. FlowSense interacts with applications using a simple API, translates application requests into OpenFlow rules and installs these rules on OpenFlow switches. FlowSense accepts application requests either to modify the network (e.g., install a path between two endpoints, with a specified bandwidth) or to monitor the network. To respond to these requests, FlowSense keeps an updated state of the network (e.g., topology, link utilizations) which it collects continually using OpenFlow. To install rules in the OpenFlow switches, FlowSense maintains a rule engine that optimizes the number of rules installed on switches. FlowSense offers a simple yet expressive interface to OpenFlow networks.